An Actual Image of a Black Hole Coming Soon

The article, “Scientists are months away from peering into black holes for the first time,” explains that the Event Horizon Telescope Array is one of the most geographically widespread array telescopes ever “built;” spanning four continents.  The array taps into the potential of the Atacama Large Millimeter/Submillimeter Array (ALMA). Scientists have discovered plenty of black holes, but the evidence has always been indirect. But by enlisting an array of telescopes, the Event Horizon Telescope will utilize very long baseline array interferometry to measure perturbations in gas around Sag A, the black hole at the center of our galaxy. By reconstructing what each telescope sees, a picture can emerge of whatever is happening at the center of our galaxy. And then, for the first time, we’ll see inside a black hole, which will help astronomers answer many questions about these mysterious beasts.

The two most fundamental properties of any telescope are its light-collecting area and its angular resolution. Light-collecting area describes how much light a telescope can collect, and angular resolution determines the amount of detail in telescopic images. The Event Horizon Telescope is a large array of radio telescopes around the world. As we learned from the power point slides in class, this is a technique used by astronomers called interferometry which allows two or more individual telescopes to achieve the angular resolution of a much larger telescope. This telescope is using very long baseline interferometry which combines radio signals from telescopes all over the earth. By using this technique, an image can emerge of a black hole from the combination of these telescopes. The Event Horizon Telescope uses radio dishes in which the focal point can be above or in the dish and an antenna is used instead of a camera. According to the power point slides, radio waves are electromagnetic radiation like light and need large dishes to get good resolution. Objects in space behave differently in radio frequencies. Visible light shows the thermal properties of stars and radio shows the behavior of gases between stars. The Event Horizon Telescope is ground-based because only radio waves, visible light, and small parts of the infrared spectrum can be observed from the ground, which we learned from the lecture tutorial, “Telescopes and Earth’s Atmosphere.” Radio telescopes can observe day and night. Some telescopes are placed in space so they are not subject to problems caused by light pollution, atmospheric distortion of light, or the fact that most forms of light do not penetrate through the atmosphere to the ground.

I found this article to be very interesting because I have always been curious about black holes and it is exciting to think that we could get an actual image of one very soon. I also liked this article because it connects to our ninth objective very well by explaining what type of telescope(s) will be used to form an image of a black hole and the technique that will be used to achieve this. It was a very informative and intriguing article.


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